Looking at astrobiology, Vance [9] reviews evidence for the occurrence of serpentine on Mars, Enceladus, Titan and Europa, and details a model for the rate of advance of a cracking front that predicts the extent of serpentinization and associated hydrogen generation over time as these bodies cooled. et al. Finally, Hansen [10] document experiments on nanoindentation of the serpentine polymorph antigorite indicating that deformation at high pressures is dominated by sliding on shear cracks rather than dislocation movement.

McClymont, E.L., Ford, H.L., Ho, S.L., Tindall, J.C., Haywood, A.M., Alonso-Garcia, M., Bailey, I., Berke, M.A., Littler, K., Patterson, M., Petrick, B., Peterse, F., Ravelo, A.C., Risebrobakken, B., De Schepper, S., Swann, G.E.A., Thirumalai, K., Tierney, J.E., van der Weijst, C., White, S., 2020. Lessons from a high CO world: an 2 ocean view from ~3 million years ago. Climate of the Past Discussions 2020, 1-27.

https://www.clim-past-discuss.net/cp-2019-161/ A range of future climate scenarios are projected for high atmospheric CO concentrations, given uncertainties 2 over future human actions as well as potential environmental and climatic feedbacks. The geological record offers an opportunity to understand climate system response to a range of forcings and feedbacks which operate over multiple temporal and spatial scales. Here, we examine a single interglacial during the late Pliocene (KM5c, ca. 3.205 ± 0.01 Ma) when atmospheric CO concentrations were higher than pre-industrial, but similar 2 to today and to the lowest emission scenarios for this century. As orbital forcing and continental configurations were almost identical to today, we are able to focus on equilibrium climate system response to modern and near-future CO . Using proxy data from 32 sites, we demonstrate that global mean sea-surface temperatures 2 were warmer than pre- industrial, by ~ 2.3 ºC for the combined proxy data (foraminifera Mg/Ca and alkenones), or by ~ 3.2 ºC (alkenones only). Compared to the pre-industrial, reduced meridional gradients and enhanced warming in the North Atlantic are consistently reconstructed. There is broad agreement between data and models at the global scale, with regional differences reflecting ocean circulation and/or proxy signals. An uneven distribution of proxy data in time and space does, however, add uncertainty to our anomaly calculations. The reconstructed global mean sea-surface temperature anomaly for KM5c is warmer than all but three of the PlioMIP2 model outputs, and the reconstructed North Atlantic data tend to align with the warmest KM5c model values. Our results demonstrate that even under low CO emission scenarios, surface ocean warming may be 2 expected to exceed model projections, and will be accentuated in the higher latitudes.

McCollom, T.M., Klein, F., Solheid, P., Moskowitz, B., 2020. The effect of pH on rates of reaction and hydrogen generation during serpentinization. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 378, 20180428.

https://doi.org/10.1098/rsta.2018.0428 A series of three laboratory experiments were conducted to investigate how pH affects reaction pathways and rates during serpentinization. Two experiments were conducted under strongly alkaline conditions using olivine as reactant at 200 and 230°C, and the results were compared with previous studies performed using the same reactants and methods at more neutral pH. For both experiments, higher pH resulted in more rapid serpentinization of the olivine and generation of larger amounts of H for comparable reaction times. 2 Proportionally greater amounts of Fe were partitioned into brucite and chrysotile and less into magnetite in the experiments conducted at higher pH. In a third experiment, alkaline fluids were injected into an ongoing experiment containing olivine and orthopyroxene to raise the pH from circumneutral to strongly alkaline conditions. Increasing the pH of the olivine-orthopyroxene experiment resulted in an immediate and steep increase in H production, and led to far more extensive reaction of the primary minerals compared to a similar 2 experiment conducted under more neutral conditions. The results suggest that the development of strongly alkaline conditions in actively serpentinizing systems promotes increased rates of reaction and H production, 2 enhancing the flux of H available to support biological activity in these environments. 2